This invention relates generally to an automatic retractable shade and more particularly to a new and novel shade unit for use in automobiles to protect the inside of a parked automobile from the deleterious effect of solar radiation, with the unit also being adaptable to other uses in the automobile during its operation.
It is known that solar heat buildup in a closed automotive vehicle can cause the inside of the vehicle to reach extremely high temperatures. This heat buildup places a heavy load on the vehicle's air conditioner and is very uncomfortable to occupants as they enter the closed vehicle.
Solar damage from ultraviolet light coming through the windshield also causes damage to the dashboard and can destroy plastic and fabric most often used in a vehicle. Once the vehicle is being operated, the heat buildup can usually be removed by the vehicle's air conditioner or by opening the vehicle's side windows.
However another problem then becomes readily apparent. On long trips in a vehicle with children or other adults in addition to the driver, the solar radiation may also be undesirable through the vehicle's side windows, especially when the vehicle is travelling north or south in the early mornings and late afternoon.
Various devices have been tried in the past with some degree of success. The modern trend is to use a folded or pleated piece of cardboard which is positioned on the inside of the front windshield of the vehicle and leans on the dashboard, being held at the top by the vehicle's sun visors. Because of the many various sizes and shapes of windshields, this solution is only partly effective since the cardboard is usually only made in one size. In addition, the cardboard does not generally reflect solar heat but instead tends to absorb it causing additional heat transfer by conduction.
Another problem with the cardboard device is the large unprotected side areas of the windshield caused by nonparallel windshield posts. Most modern vehicle windshields are constructed in an isosceles trapezoid shape with equal length nonparallel sides and unequal length parallel top and bottom edges. Such a shape requires an acceptable device to be able to conform to the shape without extensive complicated mounting brackets.
The problem of side window solar radiation while the vehicle is being operated is oftentimes minimized by hanging a towel or large handkerchief along the window after opening the window and positioning the top of the handkerchief in the closed window. Some solar radiation is blocked by this method but the solution also is aesthetically unappealing.
Various window shade devices are known in the art as typified by the U.S. Pat. No. 289,573, to W. C. Scott, issued on Dec. 4, 1883. This device is simply a pleated window shade with a pull cord to raise and lower the shade in the window. A modified type window shade is taught in the U.S. Pat. No. 1,289,281, to W. S. Shaft, issued on Dec. 31, 1918. This pleated window shade is adjustable by cords at the top and bottom to various positions on the window. The modifications of these window shades to an automotive vehicle would result in a device which would be very cumbersome to operate, especially where two shades were mounted on opposite sides of the windshield.
A temporary curtain for covering a home window is taught in the U.S. Pat. No. 3,913,655, issued on Oct. 21, 1975. This device is a pleated paper drapery that is used temporarily by a new homeowner or renter until he can purchase the more expensive pre-made fabric materials. This device, while satisfactory for its intended use, would not be acceptable for use on an automotive windshield since no spring bias retraction device is incorporated which would result in cumbersome and bulky ties being needed to hold the device in an open position which would not obstruct the driver's normal vision while operating the vehicle.
Various spring biased mounting devices are known for use with home window shades as typified by the U.S. Pat. No. 4,205,816, to C. L. Yu, issued on June 3, 1980. Mounting such a device parallel to an angled windshield post would cause the shade to come out of the roller at an angle to the vehicle's dashboard. In order to compensate, the roller must be mounted perpendicular to the dashboard which would require bulky mounting brackets that would cause vision obstruction to the driver.
Side curtains or shades have been used in older automobiles of the early vintage type having no side windows. One typical side shade is taught in the U.S. Pat. No. 1,168,343, to E. Smith, issued on Jan. 18, 1916. This curtain is a pleated device with transparent panels 19 which are designed to presumably prevent rain, snow or air from entering the open sides of the vehicle while it is being operated. The curtain is pulled along a wire 14 or cable and is swung upwardly to clear the door space when not used. The transparent panels 19 would admit solar radiation and as such this device would not be acceptable as a windshield cover. Other problems with this device also make it unacceptable to solve the before mentioned problems.
Another type of side curtain or shade is taught in the U.S. Pat. No. 1,409,541, to E. R. Jaeger, issued Mar. 14, 1922. The device uses a pleated shade which moves on vertical rods and would be impossible to adapt to a front windshield. Transparent slits 23 or sections are designed to let in light which would negate their use on a front windshield to prevent the effects of solar radiation.
A horizontally mounted roller glare shield for use on a vehicle windshield is taught in the U.S. Pat. No. 1,648,994, issued to E. F. Pitman on Nov. 15, 1927. A semitransparent curtain is used and is held in an open position by a vacuum cup 11. To adapt this device to a modern automotive vehicle would expose a major portion of the dashboard to solar radiation since a modern vehicle generally has an outwardly sloped windshield at the bottom thereof. The patented device would be usable on a vintage automobile with a generally vertical windshield but could not be easily adapted to a sloped windshield.
A detachably outside mounted protective curtain for windshields to prevent accumulation of ice, snow or frost is taught in the U.S. Pat. No. 2,723,714, issued to M. R. Moore on Nov. 15, 1955. A conventional window shade roller with a plastic planar surface on the curtain functions as designed but could not be adapted for inside mounted solar radiation prevention on nonparallel side post windshields of modern construction as previously discussed.
A modern device to attempt to solve the solar radiation problem is taught in the U.S. Pat. No. 4,560,245, issued on Dec. 24, 1985, to P. I. Sarver. This device is an internally positioned heat transfer inhibiting curtain that is positioned folded on the dashboard when not used and is lifted upwardly when in use, being held by fastener strips 28 and 30 of the knit loop and hook type commonly known as Velcro brand types. This device will partially or totally obstruct the vehicle's defroster vents on the top of the dashboard. Should the vehicle windshield quickly fog up, as often happens while being driven, a dangerous situation would present itself as the driver tries to remove the device to allow the defroster vents to operate. Also referred to in this patent is a completely removable curtain that is externally stored. U.S. Pat. No. 4,109,957 apparently is a device for solar radiation prevention which is constructed of cloth material to reduce solar radiation.
The effectiveness of any device to protect against solar radiation is only as good as the person who uses the device. The simplicity of any device may be useful in getting the driver to discipline himself or herself to position the device every time one leaves the vehicle. The modern folded cardboard devices can often be seen lying on the back seat of the vehicle after the driver has left without the device being positioned in the windshield area, thus destroying the effectiveness of the device.
The best device would than be one that can be closed in place across the windshield, quickly and with very little effort and one that can also be opened quickly without effort so that its use is as simple as the buckling of a seat belt. Such a device would then be used more often by the driver and accordingly the interior of the vehicle would be better protected.